Best Caves with Underground Rivers
Active river caves are the most dynamic show caves: they sound different, smell different, and feel different from dry caves. The selection below covers caves where the underground river is the centerpiece of the visit.
Phong Nha Cave, Vietnam
7.7-km river cave; visitors enter by wooden boat on the Son River.
Clearwater Cave, Malaysia (Mulu)
227 km of passage, the longest cave in Southeast Asia. River boats reach the show entrance section.
Marble Arch Caves, Northern Ireland
Boat ride at the entrance follows the underground river before the walking tour begins.
Gouffre de Padirac, France
The Joly stream runs along the bottom of the chasm; boat tour for 500 metres before the chambers.
Lurgrotte, Austria
Longest active river cave open to tourists in Austria. Walking tour above the stream.
Mitchelstown Cave, Ireland
Active underground river audible throughout the tour but not visible in the walking sections — characteristic Burren hydrology.
Lehman Caves, USA
Less rivery than the others but with active percolating water and small stream features in the National Park's Great Basin caves.
Speleothems and rivers
Active river caves often have less speleothem than dry caves because flowing water removes calcium carbonate before it can deposit. The reverse can also happen: rivers can carve passages, then dry, then become decorated.
When to visit
Many river caves close in winter due to flooding risk. Spring melt can make tours unsafe — always check local advisories.
Explore on the map
See every river cave on the interactive map.